It terms of blurring the high-resolution train model - here is something you could try out:

First scale the train model to 70 % or even 65% (you may need to tweak with it a bit). Let us say you scaled it down by x%. After that again scale it up by (100-x)%. By doing this, you are loosing some detail (x% amount of detail actually), and there by should reduce the resolution of the train.

After that compose the train and the track and apply a very light Gaussian blur.

Try it out and let us know.